Bacterial 'Vampires' Suck Life Out of Other Microbes

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I want to suck your … bacteria? A "vampire" bacteria species,
which survives solely by sucking the life out of other bacteria,
has had its genome sequenced, revealing its potential to serve as
a living antibiotic.

Researchers discovered that the bacterium hunts down prey and
attaches itself to the outer layer, or cell wall, of its victim,
then sucks them dry of nutrients and energy. In the end, the
"victim" bacteria is dead, which could present a very useful
strategy for treating
bacteria-based human diseases.

"Pathologists may eventually be able to use this bacterium to
fight fire with fire, so to speak, as a bacterium that will
aggressively hunt for and attack certain other bacteria that are
extremely harmful to humans," study researcher Martin Wu said in
a statement.

What makes vampire bacteria tick

Micavibrio aeruginosavorus was discovered over 30 years
ago in wastewater. It has been difficult to study in the lab,
however, because it is contaminated by the other bacteria it
feeds on.

The genome showed that the vampire bacteria aren't able to
survive on their own, even if all vital nutrients are available.
That's because they don't have the genes necessary to transport
some integral nutrients through their cell wall, so they need to
get them directly from other bacteria.

The team also discovered a group of genes that likely play a role
in how the vampire bacteria seek out and attach to their prey,
and genes that enable them to transport nutrients and energy from
the bacteria they eat.

The researchers analyzed what genes were turned on during
different phases of the bacteria species' life. When they are "on
the hunt," before they settle into their vampirelike existence,
genes were turned on that regulated the movement of the
bacteria's tail and the sensing of chemical signals in the
environment. But during the attach-and-suck-dry phase, the
researchers noticed that genes involved in protein production got
turned on. Those genes likely helped to build the bridges between
the two bacterial cells and for the vampire bacteria to grow and
divide in response to the available nutrients.

Vampire treatment

Scientists have known that these kinds of vampire bacteria
species attack many different kinds of bacteria, including those
that cause chronic lung infections in people with cystic
fibrosis. If this vampire could be tamed to kill off these lung
infections, it could greatly
improve survival of cystic fibrosis patients who often
succumb to lung complications of their disease by the time they
reach 40, the researchers said.

New approaches like these are needed to control bacterial
populations, especially those dangerous to human health, Wu said.
Traditional antibiotics breed resistance as the bacteria adapt to
the drugs and "escape" their antibacterial effects. This resistance
leads to super-bugs, bacteria that are resistant to multiple
kinds of drugs.

Using a living antibacterial agent like the vampire bacteria
would enable this bacterial "treatment" to adapt along with the
harmful bacteria, decreasing the likelihood that this resistance
would develop, the researchers noted. With the sequence of the
vampire bacteria genome in hand, researchers will be able to
better understand how it seeks out and attacks specific kinds of
bacterial prey. This could, eventually, enable the scientists to
tailor-make vampire bacteria to attack just a single type of
disease causing bacteria.

"It is possible that a living antibiotic such as M.
aeruginosavorus — because it so specifically targets certain
pathogens — could potentially reduce our
dependence on traditional antibiotics and help mitigate the
drug-resistance problem we are now facing," Wu said.

The study was published Sept. 21 in the journal BMC Genomics.

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